This invention is concerned with the manufacture of stand-up pouches, and more particularly with the manufacture of liquid-filled stand-up (self-supporting) pouches of thermoplastic film, by a vertical form, film, seal (F/F/S) machine.
At present, horizontal F/F/S machines are used to package dry flowable products. Liquid filling of stand-up pouches, when performed on such machines, is generally limited to small volume pouch sizes. This is a reflection of the manner in which the machines operate.
In a horizontal machine, before a pouch is filled it is completely formed, with the exception of an open top. To fill the pouch, it is handed off to a set of grippers on a rotating, intermittent motion filling/sealing section. The grippers are actuated to open the top of the pouch, and a predetermined quantity of a free flowing product is funneled into the pouch. The top is then heat sealed.
Handling large volumes of liquid in pouches on a rotating, intermittent motion filling/sealing section is difficult, because of the weight of the liquid and its fluidic activity.
Horizontal machines have limitations in addition to pouch size. The step-up or pull length of the pouch is not easy to modify, since the grippers that open the top of the pouch must be set to the exact pouch width. Since a number of pouches may be open and exposed to the surrounding environment during filling, it may be necessary to provide an enclosure and filtration or over-pressurization apparatus to avoid product contamination. Furthermore, the placement of fitments and the types of pouch films that can be used tend to be limited.
Vertical machines have been used to produce liquid-filled pouches. See, e.g., commonly owned U.S. Pat. No. 4,947,621, incorporated herein by reference. However, such machines are not designed to produce stand-up pouches.